The present invention relates to an apparatus for warming up an automatic developing system. More particularly, the present invention is concerned with an apparatus which is capable of completing warm-up of an automatic developing system by the time at which the developing operation is to be commenced.
Automatic developing systems have been known are adapted to automatically perform a series of treatment such as development, fixing and rinsing on photosensitive materials such as photographic films and print papers. Usually, such automatic developing systems are used cyclically such that they are started every morning and stopped in the evening. The temperature of the developing solution in the system, therefore, starts to fall after the stop of operation of the system, so that the system as a whole is cooled down by the next morning. It is, therefore, necessary to warm up the system before it is used. More strictly, it is required that the system be completely warmed up by a time which is a predetermined time before the scheduled commencement of operation of the developing system.
Hitherto, it has been a common practice to set a mechanical or electric timer to start a warming apparatus such that it completes the warming, i.e., the temperature control of the liquid, by a predetermined time before the use of the automatic developing apparatus.
However, since this conventional warming apparatus operates on the basis of an estimated time required for the warming, it is often experienced that the temperature of the developing solution cannot be raised to the required level by the time at which the automatic developing system is to be started, with the result that the user cannot commence the treatment of the photosensitive material at the expected time. This problem will be overcome if the timer is set such that the warming apparatus operates for a longer time. In such a case, however, the warming tends to be finished well in advance of the time at which the developing system is to be started. In consequence, the warming apparatus has to operate wastefully so as to control the liquid temperature at a suitable level, resulting in a wasteful use of the energy such as that consumed by a heater.